This invention pertains to ink jet printing and more particularly to ink jet printing of wide format substrates such as textiles.
The printing of textiles is currently accomplished primarily by rotary screen methods. In operation, screen printing is rapid and, for large runs, cost effective. However, cutting screens is expensive and time consuming thus making the per unit cost for short runs and strike-offs quite substantial and, in many cases, prohibitive.
A digital printing method such as ink jet printing offers a number of potential benefits over conventional screen printing methods. Digital printing eliminates the set up expense associated with screen preparation and can potentially enable cost effective short run production.
Ink jet printing furthermore allows visual effects such as tonal gradients and infinite pattern repeat size which can not be practically achieved by a screen printing process.
A disadvantage of ink jet printing, as it exists today, is relatively slow print speed. Current ink jet printers print at a rate of about 1-10 m2/hr max compared to a rate of greater than 1000 m2/hr for screen printing. To be competitive even for short runs, therefore, the speed of ink jet printers needs to be increased.
Another current disadvantage of ink jet printing is the limited amount of colorant and other solids an ink jet ink can contain. Ink jet printing cannot deliver the balance of vivid color as well as end use performance (durability) expected for production quality prints, particularly with pigmented inks. Also, pretreatment of textile fabrics has been required to get good color thus adding an additional step and cost to the manufacturing process. Prints on pretreated fabric may be more susceptible to pigment removal by abrasion and thus have reduced durability and wash fastness.
Yet another current disadvantage of ink jet printing is the limited number of inks which can be practically used on an ink jet printer at any one time. Screen printing can employ twenty or more (typically 10-13) mother colors which can provide a very wide gamut. Ink jet printers have traditionally been limited to no more than about six colors. Ink jet ink colors must thus be chosen judiciously in order to achieve a gamut similar to that of screen printing.
It is an objective of this invention to provide an ink jet printing system adapted for high speed printing of textiles.
A further objective of this invention is to provide inks which are formulated to deliver both high color expression and good durability on untreated fabrics as well as a broad gamut with a limited number of colorants.
A further objective of this invention is to provide a system which can optimally predict and control ink jet printer output to obtain the desired image quality.
Thus, there is provided a system for printing an image on a wide format recording medium (such as a textile) with an ink jet printer, wherein said system can simulate screen printing, comprising a computer interconnected to an ink jet printer, said ink jet printer being adapted for the printing of said wide format medium, preferably with an aqueous ink jet ink, and more preferably with a pigmented aqueous ink jet ink, wherein said computer is programmed to:
(1) accept a data input constituting said image in a plurality of acceptable file formats, at least one of said acceptable file formats being an indexed RGB file format, and at least another of said acceptable file formats being a monochromatic image format;
(2) transform said data input from said acceptable file format into a suitable L*a*b* file format;
(3) convert said suitable L*a*b file format into a driver format which can drive said ink jet printer to print said image on said wide format recording medium; and
(4) communicate said driver format to said printer.
Said computer can optionally also be programmed to limit the color gamut of said image in said L*a*b file format to fall within an estimated screen gamut of said screen printer, by mapping said color gamut of said image in said L*a*b file format against said estimated screen gamut of said screen printer so that said color gamut is limited to said estimated screen gamut. The color gamut limited L*a*b file format is then converted into a driver format in step (3) above.
There is also provided a system for printing an image on a wide format recording medium (such as a textile) with an ink jet printer, wherein said system can simulate screen printing, comprising a computer interconnected to an ink jet printer, said ink jet printer being adapted for the printing of said wide format medium, preferably with an aqueous ink jet ink, and more preferably with a pigmented aqueous ink jet ink, wherein said computer is programmed to:
(1) accept a data input constituting said image in an acceptable file format selected from the group consisting of an indexed RGB file format and a monochromatic image format;
(2) transform said data input from said acceptable file format into a suitable L*a*b* file format;
(3) map said color gamut of said image in said L*a*b file format against an estimated screen gamut of said screen printer so that said color gamut is limited to said estimated screen gamut;
(4) convert said color gamut limited L*a*b file format into a driver format which can drive said ink jet printer to print said image on said wide format recording medium; and
(5) communicate said driver format to said printer.
In another aspect of the present invention, there is provided a method for printing an image on a wide format recording medium (such as a textile) with a system comprising a computer interconnected to an ink jet printer, adapted for the printing of said wide format medium, preferably with an aqueous ink jet ink, and more preferably with a pigmented aqueous ink jet ink, comprising the steps of:
(1) accepting into said computer a data input constituting said image in a plurality of acceptable file formats, at least one of said acceptable file formats being an indexed RGB file format, and at least another of said acceptable file formats being a monochromatic image format;
(2) transforming in said computer said data input from said acceptable file format into a suitable L*a*b* file format;
(3) converting in said computer said suitable L*a*b file format into a driver format which can drive said ink jet printer to print said image on said wide format recording medium; and
(4) communicating said driver format to said ink jet printer to drive said ink jet printer to print said image on said wide format recording medium.
Optionally, the color gamut of said image in said L*a*b file format can be limited to fall within an estimated screen gamut of said screen printer, by mapping said color gamut of said image in said L*a*b file format against said estimated screen gamut of said screen printer so that said color gamut is limited to said estimated screen gamut. The color gamut limited L*a*b file format is then converted into a driver format in step (3) above.
There is also provided a method printing an image on a wide format recording medium (such as a textile) with a system comprising a computer interconnected to an ink jet printer, adapted for the printing of said wide format medium, preferably with an aqueous ink jet ink, and more preferably with a pigmented aqueous ink jet ink, comprising the steps of:
(1) accepting into said computer a data input constituting said image in a plurality of acceptable file formats, at least one of said acceptable file formats being an indexed RGB file format, and at least another of said acceptable file formats being a monochromatic image format;
(2) transforming in said computer said data input from said acceptable file format into a suitable L*a*b* file format;
(3) mapping in said computer said color gamut of said image in said L*a*b file format against an estimated screen gamut of said screen printer so that said color gamut is limited to said estimated screen gamut;
(4) converting in said computer said color gamut limited L*a*b file format into a driver format which can drive said ink jet printer to print said image on said wide format recording medium; and
(5) communicating said driver format to said ink jet printer to drive said ink jet printer to print said image on said wide format recording medium.
Another aspect of the present invention relates to a method of limiting the color gamut of an image in data form to an estimated screen gamut of a screen printer, comprising the steps of:
(1) estimating the screen gamut of a screen printer to produce said estimated screen gamut;
(2) mapping said color gamut of said image against said estimated screen gamut to identify one or more colors of said color gamut that fall outside of said estimated screen gamut; and
(3) reassigning said identified one or more colors in said color gamut to a color within said estimated screen gamut to produce a gamut limited color gamut.
As indicated above, one preference in the above methods is to use a pigmented aqueous ink jet ink. Another aspect of the present invention is a particular new type of aqueous ink jet ink that has, for example, been found particularly suitable for the printing of textile substrates, said ink comprising an aqueous medium, a pigment as a colorant, and a polymer binder, wherein:
said ink has a viscosity of 10-30 cps at 25xc2x0 C.,
said polymer binder comprises one or more dispersed polymers,
the binder to pigment weight ratio is greater than about 2, and
the total of binder plus pigment is at least about 15% by weight of the ink.
Said inks are advantageous in, for example, providing good crock fastness.
For good color gamut, vivid color and high durability of the printed image with a limited number of colorants, yet another aspect of the present invention provides an ink jet color set of eight inks comprising:
(a) a first magenta ink comprising a quinacridone pigment, preferably PR 122, and carrier;
(b) a second magenta ink, referred to as medium magenta, comprising a quinacridone pigment and carrier, wherein the pigment is the same pigment as in the first magenta ink but is present as a weight percent in an amount from about 5-90% (preferably 5-50%) of that of the first magenta ink;
(c) a first cyan ink comprising a copper phthalocyanine blue pigment, preferably PB 15:3, and carrier;
(d) a second cyan ink, referred to as medium cyan, comprising copper phthalocyanine blue pigment and carrier, wherein the pigment is the same pigment as in the first cyan ink but present as a weight percent in an amount from about 5-90% (preferably about 5-50%) of that of the first cyan ink;
(e) a yellow ink comprising a diarylide yellow pigment, preferably PY 14, and carrier;
(f) an orange ink comprising a diarylide orange pigment, preferably PO 34, and carrier;
(g) a green ink comprising a copper phthalocyanine green pigment, preferably PG 36, and carrier, and
(h) a black ink comprising a carbon black pigment and carrier.
The inks are preferably aqueous ink jet inks, and more preferably aqueous ink jet inks having the characteristics mentioned above.
These and other features and advantages of the present invention will be more readily understood by those of ordinary skill in the art from a reading of the following detailed description. It is to be appreciated that certain features of the invention which are, for clarity, described above and below in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination.